Currently, as environment pollution has become a more serious problem, use of pollution-free energy has become more important. In particular, air pollution in large cities has gradually become more serious, and vehicle exhaust gas is one of the major sources thereof.
Accordingly, in order to reduce the amount of exhaust gas and to provide more efficient fuel consumption, environmentally-friendly vehicles including hybrid vehicles and electric vehicles have been developed and driven.
An environmentally-friendly vehicle may be a vehicle that does not discharge an exhaust gas. Such an environmentally-friendly vehicle may include a pure electric vehicle that drives using the power of a motor, a hybrid electric vehicle that combines and drives using the power of a motor and an engine, and a fuel cell vehicle that drives using the power of a motor driven by electricity that is generated in a fuel cell.
Such an environmentally-friendly vehicle mounts a high voltage battery as an electric power source that drives a drive motor and a converter.
Currently, a drive motor uses a field coil motor rather than a permanent magnet motor.
Here, because the field coil motor may be formed without a rare earth metal and has a wide driving area, the field coil motor may be a representative motor that can replace a permanent magnet motor. By winding a coil to an iron core of each of a stator and a rotor and by applying a current thereto, the field coil motor generates a torque.
Because such a field coil motor may replace a permanent magnet for generating a field magnet magnetic flux with a coil, the field coil motor has different electrical response characteristics according to a field magnet current. In particular, when a drive motor drives with a maximum efficiency control that minimizes a loss, it is advantageous in efficiency, but a dynamic response performance thereof may be deteriorated due to an increase in rotor inductance.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.